In photographic printing papers, the surface of the raw paper to be emulsion-coated is generally covered by a polyolefin layer in which titanium oxide has been dispersed by kneading so as to improve water resistance and light reflectance. However, although the polyolefin is very flexible and easy to work with, it is not very tough. It was therefore necessary to increase the thickness of the covering, which adversely affected the gloss.
The aforesaid problems inherent in photographic printing paper supports using polyolefin are resolved by using a composition containing essentially polyethylene terephthalate (PET) instead of polyolefin (Japanese Patent Application Hei 389983).
However, if the conventional method of hot extruding a composition containing mainly PET is used, and the hot extruded drip film falls very close to the nip point of the nip roll and chilled roll while the paper is being transported between them, the thickness of the laminated film in the width direction is generally not uniform and mass production is rendered difficult. In addition, it was not possible to obtain sufficient adhesive strength of the covering layer to the paper support.
The Inventors, as a result of intensive studies, found that a covering layer of uniform thickness can be obtained by allowing the hot drip film to fall onto the paper support on the nip roll. They also found that even more satisfactory results can be obtained by arranging the temperature of the nip roll to lie within the range 30.degree.-250.degree. C. but preferably within the range 50.degree.-130.degree. C., and by arranging the discharge direction of the hot extruded film to coincide with the tangential direction of the nip roll.